1. Field of the Invention
The present invention relates to a rotary electric machine capable of suppressing a deflection, which can be used as a floppy disk drive, for example.
2. Description of the Prior Art
A rotary electric machine for a floppy disk drive as shown in FIG. 6 is known. In FIG. 6, a cylindrical bearing holder 10 is secured onto a frame 8 which also serves as a circuit substrate, and a stator core 7 is secured by fitting on the outer periphery of the bearing holder 10. The core 7 has a suitable number of poles, each having a drive coil 6 wound about it. The core 7 and the coil 6 constitute a stator. A spindle 4 is rotatably supported in the inner periphery of the bearing holder 10 by a pair of upper and lower metal bearings 5, 5. The lower end of the spindle 4 rests on a thrust receiver washer 9. A hub support 3 is secured by fitting to the upper end of the spindle 4 which projects from the upper end of the bearing holder 10. A center portion of a flat and cup-like rotor case 2 is secured by fitting onto the hub support 3 from underneath. The rotor case 2 is arranged to cover the stator portion. A ring-like drive magnet 1 is secured to the inner periphery of the rotor case 2, and the inner peripheral surface of the drive magnet 1 is spaced from and opposed to the outer peripheral surface of the stator core 7. The drive magnet 1, rotor case 2, hub support 3 and spindle 4 constitute a rotor. The rotor is arranged opposed to the stator and is rotatively driven by the magnetic action between the drive coil 6 constituting the stator and the aforesaid pole. The hub portion of the floppy disk is placed on the hub support 3 as is known and as the rotor rotates, the floppy disk also rotates.
According to the conventional rotary electric machine, since no radial force is applied to the rotor, a deflection occurs in the spindle 4 through a clearance between the metal bearings 5, 5 and the spindle 4 when the rotor rotates. The deflection of the spindle 4 is a random and non-repeatable deflection, which when used for the floppy disk drive, for example, results in a read error and a write error resulting from a track deflection of the floppy disk with respect to a transducer for a magnetic head or the like.